replace comparisons with bit math bullshit

integers in the range [0, 15] fit entirely in the bit mask 0x000F. integers out of that range will have at least one bit 0x0010 or higher, or will have the sign bit 0x8000 set. so to find out if one of two numbers is out of range [0, 15], we can check the bit mask of their bitwise or.

this saves tokens and cycles. it is also completely illegible. very in the spirit of Pico-8, I love it.
This commit is contained in:
2022-12-22 22:49:27 -08:00
parent 10948ce4a5
commit fe3a68284f

View File

@ -438,7 +438,7 @@ function level:spawn_exit()
if (self:_mget(x,y)!=18) return
for nx=x-1,x+1 do
for ny=y-1,y+1 do
if nx<0 or ny<0 or nx>15 or ny>15 then
if (nx | ny) & 0xFFF0 ~= 0 then
self._wins[_mix(nx,ny)]=true
end
end